In recent years, it has been clarified that sugar chain present in the cell surface is deeply involved in various vital phenomena (cell recognition, transduction of information, cell adhesion, differentiation and proliferation, canceration, virus infection, blood coagulation, immune reaction and the like). When the target molecule in the phenomenon is a sugar chain, the interaction is classified into a “sugar chain-sugar chain” interaction, and when the target molecule is a protein, it is classified into a “sugar chain-protein” interaction. In the former, cell surface sugar chains in a particular sugar chain structure combinatory relationship are bound to each other. In the latter, one of the cell surface sugar chains recognizes and binds to a sugar chain recognition protein on the other cell surface, where lectin, glycosyltransferase and glycohydrolase are said to be involved as the sugar chain recognition protein. Inspired by such vital phenomenon, the development and research of a physiological material (cell or protein isolation material, device, sensor), pharmaceutical products and the like, incorporating a sugar chain, has been actively performed (e.g., non-patent documents 1, 2 and 3).
For the development of a sugar chain-containing functional material that expresses a desired physiological function, the correlation between the structure and physiological activity of a sugar chain needs to be studied at molecular and functional group levels, as well as a technique to freely modify a sugar chain molecule and introduce same into a polymer is required.
With these backgrounds, various sugar chain-containing polymers have been reported. For example, as polymers incorporating a sugar chain such as monosaccharide, disaccharide, oligosaccharide and the like (hereinafter sugar chain polymer),    1. polyvinyl alcohol type (e.g., patent document 1)    2. polyacrylate type (e.g., patent document 2)    3. polystyrene type (e.g., patent documents 3-8)    4. polyether type (e.g., patent document 9)    5. polyethyleneimine type (e.g., patent documents 10 and 11)    6. polyamino acid type (e.g., patent documents 12-16)    7. polyurethane type (e.g., patent document 17)and the like are known. Among these, patent document 5 discloses selective adhesion and collection of hepatocytes as well as cancer cell recognition using a sugar chain polymer-coated substrate.
In recent years, a cell treatment has been practiced wherein cells contained in body fluids such as blood, bone marrow and the like are isolated and transplanted for the purpose of regeneration of tissues such as blood vessel and the like as well as immunomodulation of cancer patients. Along therewith, various materials, devices and the like for selectively isolating cells useful for the treatment have been developed. Among the cells present in body fluids represented by blood, monocyte has blood vessel regeneration capability (non-patent documents 4, 5), and is drawing attention as a precursor cell of a dendritic cell to be used for a dendritic cell therapy, which is one of the cell immunity therapies (non-patent document 6). As a method for isolating monocytes from a body fluid such as blood and the like, the following have been reported.
Examples of a method of isolating peripheral blood monocytes include a density-gradient centrifugation method wherein the difference in the specific gravity of the cells is utilized for isolation, a method wherein a blood component containing monocytes is isolated from the peripheral blood by apheresis and the like, highly adhesive monocytes are attached to a physical and chemical instrument such as a polystyrene flask and the like, and non-adhesive cells are removed to isolate the monocytes, a method wherein monocytes are selectively isolated by utilizing magnetic beads bound with an antibody to the monocyte and the like. The isolated monocytes are cultured with cytokine such as IL-4, GM-CSF and the like to induce differentiation into dendritic cells, which are used as cancer treatment cells.
However, the method of isolating monocytes by the density-gradient centrifugation method is associated with many problems yet to be solved, such as a safety problem of the liquid to be used for density gradient (cytotoxicity and the like), an operability problem because of a long time required for centrifugation, washing operation and the like, much loss of cells, an open system operation allowing easy contamination and the like, isolation efficiency (insufficient removal of non-adhesive cells, contamination with lymphocytes) and the like.
Moreover, a method including isolation of mononuclear cells by the density-gradient centrifugation method, and selective attachment of monocytes to a physical and chemical instrument such as plastic dish and the like by utilizing the difference in the adhesion of monocytes and lymphocytes to a substrate is known. However, this method requires complicated operation, and the recovery rate and purity of the isolated monocytes are not sufficient.
The isolation method using magnetic beads with antibody can isolate monocytes at a comparatively high purity, but the cell treatment requires a long time, and also, is expensive.
In the elutriation method, a cell suspension is centrifuged in a chamber having a slope, while flowing a buffer in an opposite direction from the centrifugation to form a particular cell layer. This method affords high purity monocytes, but the apparatus is expensive, and requires a skillful operation technique. In addition, the cell isolation problematically requires a long time.
In recent years, moreover, a monocyte isolation method using a cell isolation filter has been reported.
For example, patent document 18 discloses a method of collecting nuclear cells by trapping nuclear cells on a filter that traps nuclear cells but passes red blood cells, and inducing a liquid current in the opposite direction from the first liquid flow direction. However, this document is directed to a filter for collecting nuclear cells, where selectivity to monocyte is absent.
In addition, patent document 19 discloses monocyte and/or monocyte-derived macrophage selective removal filter apparatus. However, this document is directed to a physical filtration filter wherein the average pore cross sectional area and bulk density of the filter were defined in consideration of the particle size of macrophage, which is clearly different from the present invention wherein monocytes are selectively isolated utilizing the affinity for the monocytes.
Patent document 20 also discloses that the monocyte trap rate increases by defining the packing density and fiber diameter of the filter. For the same reasons as mentioned above, it is clearly different from the present invention. In addition, the property is not sufficient because the monocyte recovery rate is about 50% and the purity is about 40%.
Lectin widely present in the biological world including animals, plants, microorganisms etc. is a generic term of proteins that recognize a sugar chain. Lectin specifically binds to a sugar chain having a particular structure, which is present in blood cell, cell surface and the like, and has an activity to aggregate blood cells and cells. For example, sword bean-derived concanavalin A (ConA) and wheat germ agglutinin (WGA) are known to aggregate malignant cells. As mentioned above, lectin is medically highly useful as a cell fractionation reagent, clinical diagnostic reagent, clinical therapeutic drug and the like, based on its sugar chain binding specificity, blood type specificity, anticancer effect and the like. At present, a wide variety of lectins are isolated from various individuals, and their functions are being strenuously examined. To further clarify the property of undeveloped lectin and develop practical use, a technique for efficient isolation and purification of useful lectin at a low cost is required (non-patent documents 7, 8).
As a conventional protein isolation method, a fractionation method utilizing difference in solubilities (salting out, fractional precipitation by organic solvent, acidic precipitation and isoelectric point precipitation), and fractionation by column chromatography (ion exchange chromatography, hydrophobic chromatography, gel filtration chromatography, affinity chromatography) are known. For isolation and purification of lectin, one kind of protein, from a naturally occurring substance such as pulse and the like, isolation from contaminating protein, fat, sugar, amino acid etc. is required, and as a method therefor, a combination of the above-mentioned methods (ion exchange and gel filtration chromatography after salting out) has been employed. However, such method cannot isolate lectin sufficiently, and high purity lectin cannot be obtained problematically. Therefore, for example, affinity chromatography using a carrier having a sugar such as maltose, lactose and the like immobilized thereon as a ligand (patent documents 21-24), and affinity chromatography using a methacrylate polymer bound with a sugar such as maltose, lactose (patent document 25), albumen-derived sugar chain (patent document 26) and the like have been utilized. As shown, various materials and methods for isolating lectin have been disclosed.
Nevertheless, since this method requires chemically binding a sugar ligand onto the carrier surface, the sugar density is not sufficient, lectin is not sufficiently isolated, and high purity lectin cannot be obtained problematically.
Sulfated sugar is known to have affinity for influenza virus and AIDS virus, and development of a new material capable of trapping viruses utilizing the principle and its production method is desired. With such backgrounds, various sulfated sugar chain-containing polymers have been reported. For example, a sulfated galactose-inducing polyacrylate type (e.g., patent document 27), sulfated sugar-inducing polyethylene type (e.g., patent document 28), sulfated glucosamine-inducing polyethylene type (e.g., patent document 29) and the like are known.
The biological functions such as recognition, adhesion and the like of cell, protein containing lectin or virus are expressed due to a “sugar chain-sugar chain interaction” or a “sugar chain-protein interaction” between a sugar chain aggregate (cluster) on the cell surface and a sugar chain aggregate complementary thereto, and the strength of the interaction is known to correlate with the sugar chain density. Since only one sugar chain such as monosaccharide, disaccharide, oligosaccharide and the like can be linearly introduced per repeat unit into the sugar chain polymers disclosed in the above-mentioned patent documents 1-17 and 25-29, the number of repeat units having a sugar chain introduced thereinto in a polymer chain needs to be increased so as to sufficiently express the biological function (recognition, adhesion and the like to cell, protein, containing lectin and virus) of sugar chain by increasing the sugar chain density in the sugar chain cluster. On the other hand, this may result in the degradation of the film forming capability, mechanical intensity and the like that skeleton polymers inherently show.
From the aspects of biocompatibility and blood compatibility, the polyurethane type sugar chain polymer disclosed in patent document 17 is preferable. However, since the production step for introducing a sugar chain into the side chain requires complicated protection and deprotection operations, the production cost may problematically increase.    patent document 1: JP-A-63-238105    patent document 2: JP-A-63-68603    patent document 3: JP-A-7-304788    patent document 4: JP-A-8-253495    patent document 5: JP-A-8-319317 (JP-B-3053764)    patent document 6: JP-A-8-253495    patent document 7: JP-A-2002-88094    patent document 8: JP-A-2005-112987    patent document 9: JP-A-5-140294    patent document 10: JP-A-5-140213    patent document 11: JP-A-2002-302511    patent document 12: JP-A-5-178986    patent document 13: JP-A-8-337566    patent document 14: JP-A-9-227600    patent document 15: JP-A-11-60603    patent document 16: JP-A-2003-73397    patent document 17: JP-A-11-71391    patent document 18: WO98/32840    patent document 19: JP-A-9-75076 (JP-B-3812909)    patent document 20: JP-A-2004-129550    patent document 21: JP-A-62-201641    patent document 22: JP-B-2660175    patent document 23: JP-A-10-504287    patent document 24: JP-B-3711356    patent document 25: JP-A-63-68603    patent document 26: JP-B-1995189    patent document 27: JP-A-11-315091    patent document 28: JP-A-2004-526691    patent document 29: JP-A-2005-15451    non-patent document 1: Design and Physiology of Sugar Chain Molecule, 2001, Japan Scientific Societies Press    non-patent document 2: Method of Studying Physiologically Active Sugar Chain, 1999, Japan Scientific Societies Press    non-patent document 3: Carbohydrate Engineering and Production Technique, 1993, Science Forum Inc.    non-patent document 4: Proc. Natl. Acad. Sci., vol. 100, No. 5: 2, 426-2431, 2003    non-patent document 5: Cardiovasc. Research, 49(3): 671-680, 2001    non-patent document 6: Cancer Res., vol. 59: 56-58. 1999    non-patent document 7: New Biochemical Experiment Course 1 Protein isolation, purification, properties, 1993, Ed. The Japanese Biochemical Society, Tokyo Kagaku Dozin Co., Ltd.    non-patent document 8: Lectin, N. Sharon•H. L is ed., translated by Toshiaki Ohsawa•Yukiko Konami, 1989, Japan Scientific Societies Press